The results are significant because they could lead to novel methods for diagnosis and treatment of PTSD, said Dr. Prakash Nagarkatti, associate dean and Carolina Distinguished Professor at the USC medical school, who is the lead researcher in this study.

The findings also are the basis for a new, $1.72 million grant from the National Institutes of Health to Nagarkatti and his team of researchers, who will intensify their research on the pathological basis of immune dysfunction in war veterans with PTSD.

“PTSD is a psychiatric condition with long-lasting symptoms that can occur after exposure to extremely stressful life events,” Nagarkatti said. “Patients with PTSD are six times more at risk of committing suicide, and the annual loss of productivity in the United States is estimated to be approximately $3 billion.”

Nagarkatti said that about 30 percent of Vietnam War veterans developed PTSD during, or at some point after, the Vietnam War, and more than 35 percent of returned Iraq and Afghanistan veterans have received mental health diagnoses, the most prevalent being PTSD. However, the precise physiological mechanisms that lead to the development of PTSD are not clear.

Investigators will test the basis for immune dysfunction in war veterans with PTSD. The researchers will test the hypothesis that traumatic events experienced by PTSD patients may trigger changes in cells in the immune system.

“Because the immune system and the nervous system interact closely with each other, dysregulation in one can severely affect the other, leading to the onset of clinical disorders associated with PTSD,” Nagarkatti said.